Mixture control for fuel injection pumps

ABSTRACT

Mixture control mechanism for lever-type, variable-stroke fuel injection pumps having a power fulcrum. The stroke of the pump is adjustably reduced by increasing the clearance at the power fulcrum. In a pump having primary and secondary levers, the position of the pivotal support of the secondary lever is adjusted. In a pump having one lever and a fulcrum slide member, the position of one of the supports for the fulcrum slide member is adjusted.

United States Patent Durham Oct. 16, 1973 [54] MIXTURE CONTROL FOR FUEL 3,354,876 11/1967 Durham 123/140 MP INJECTION PUMPS 3,487,821 1/1970 Skinner..... 123/140 MC 3,020,776 2/1962 May et al 123/140 MC [76] Inventor: Roger Owen Durham, 3958 Marathon St., Los Angeles, Calif. 90029 Primary ExaminerLaurence M. Goodridge [22] Filed: May 13, 1971 [21] Appl. N0.2 142,946 57 ABSTRACT 521 US. Cl. ..123/139Ac, Mixture comm mechanism for lever-type variable- 123/l39 Aw 123/140 MP 123/139 BG stroke fuel injection pumps having a power fulcrum. [51] Int. Cl. F02m 51/02 The stroke of the P p is adjustably reduced y [58] .Field of Search 123/139 R, 139 AB, increasing the clearance at the power fulcruml23/139 139 139 139 In a pump having primary and secondary levers, the 139 B6, 140 MP, 140 MC position of the pivotal support of the secondary lever is adjusted. In a pump having one lever and a fulcrum [56] References Cited slide member, the position of one of the supports for UNITED STATES PATENTS the fulcrum slide member is adjusted.

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INVENTOR .pww

MIXTURE CONTROL FOR FUEL INJECTION PUMPS BACKGROUND OF THE INVENTION This invention pertains to fuel injection pumps for internal combustion engines and the like. In particular, it pertains to mixture control mechanisms for levertype fuel injection pumps.

In the past, lever-type fuel injection pumps have used mixture control mechanisms of several types.

One was an air bleed into the sensing cylinder, which raised the pressure within it abnormally, thus causing the power fulcrum to be extended and the stroke of the pump to be increased. This enriched the idle mixture but not the running mixture, and was a gross adjustment, useful only during warm-up of the engine.

Another was by turning the tapped power fulcrum up or down on the threaded controlrod. This required the vehicle be stopped during the adjustment, and was of a semi-permanent nature. On occasion a new sensor' spring was required if the idle position of the power fulcrum was not near the supplementary fulcra.

Another mixture control mechanism has been obtained by adjusting the position of the sensor spring support within the sensor housing, or by adjusting the position of the entire sensor mechanism relative to the transmission of the fuel injection pump. Either method has produced good results, and could be operated from the drivers seat with the vehicle in motion.

The mixture control of the current invention also lends itself to use with the vehicle in motion. Idle mixture is not changed; open-throttle mixture is the most changed; and in-between throttle settings obtain proportionately varied mixtures.

SUMMARY OF THE INVENTION The current invention provides a mixture control for lever-type fuel injection pumps which can be operated from the drivers seat without stopping either engine or vehicle.

Clearance at the power fulcrum is adjustably increased, either by moving one of the supports of the fulcrum slide member, in the case of a single-levered fuel injection pump, or by moving the pivotal support of the secondary lever, in the case of the fuel injection having two levers, to decrease the stroke of the pump. A minimum clearance at the power fulcrum is always maintained during a portion of each cycle so that the power fulcrum can move up and down freely.

Accordingly, one of the objects of the invention is to provide a mixture control mechanism for lever-type fuel injection pumps which can be ajusted with the vehicle in motion.

A second object of the invention is to provide a mixture control mechanism which does not effect the idle mixture.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a median section through the transmission of a fuel injection pump having two levers and embodying the mixture control of the invention in its preferred embodiment. The pump is adjusted for maximum stroke.

FIG. 2 shows the pump of FIG. I adjusted for minimum stroke.

FIG. 3 is a median section through the transmission of a fuel injection pump having one lever and embodying the mixture control of the invention in an alternate embodiment. The pump is adjusted for maximum stroke.

FIG. 4 shows the pump of FIG. 3 adjusted for minimum stroke.

FIG. 5 shows an alternate mixture control mechanism for a pump having two levers, as adjusted for minimum flow.

FIG. 6 shows an alternate mixture control mechanism as applied to single-levered fuel injection pump. The mechanism is adjusted for minimum flow.

DETAILED DESCRIPTION OF THE DRAWINGS Referring now to FIG. 1, a fuel injection pump I having two levers is shown. Pumping and check valve means and housings are omitted.

A transmission housing 2 is bored two places to support bearings 5, said bearings 5 in turn rotatably supporting an eccentric shaft 4 which carries an eccentric 3. Said eccentric shaft 4 is driven by the engine, by means such as a vee belt and pulley combination, which is not shown.

A cover plate 6 partially closes the top of said transmission housing 2 and provides a base for the mounting of a sensor mechanism which is shown only as a rectangle. A sensor control rod 7 extends through an aperature 8 in said cover plate 6, and engages said sensor mechanism 80. Threads 24 at the end of said sensor control rod 7 engage a power fulcrum 22. During openthrottle operation, said sensor mechanism 80 extends said control rod 7 and said power fulcrum 22, as shown in all figures.

The threads of a self-locking, semi-permanent support screw 10 engage a tapped hole 29 in said transmission housing 2. At its end, a spherical seat 28 pivotally supports a primary lever 9.

At its opposite end, said primary lever 9 engages said eccentric 3. The primary lever 9 has a guide slot 21 to guide said power fulcrum 22, and two supplementary fulcra 23, one of which is shown. Said supplementary fulcra 23 are disposed on opposite sides of said guide slot 21. Said supplementary fulcra 23 bear the load of a secondary lever 11 during a portion of each cycle, thus allowing said power fulcrum 22 to be freely moved by said sensor control rod 7.

At its lower end, said secondary lever 11 is pivotally supported by a support pin 12. Said support pin 12 is slidably supported by a bore 25 in said transmission housing 2. A nose portion 13 of said support pin 12 engages an aperature 14 at the lower end of said second ary lever 11. A shoulder 26 of said support pin 12 pivotally supports said secondary lever 11. A self-locking support pin adjustment screw 27 engages internal threads in said support pin 12. The free end of said support pin adjustment screw 27 bears against a mixture control slide 16. Said support pin 12 and said support pin adjustment screw 27, together, comprise a slidable support pin means 30 adaptable at one of its ends for pivotally supporting said secondary lever 11, and adaptable at its other end for engaging said mixture control slide 16. Said mixture control slide 16 is slidably supported by slide surfaces 17 of said transmission housing 2.

A compression spring 15, positioned by said nose portion 13, keeps the lower end of said primary lever 9 in contact with said eccentric 3 and the lower end of said secondary lever 11 in contact with said shoulder 26 of said support pin 12.

The upper end of said secondary lever 11 bears against a pump element 18, reciprocation of which causes pumping to occur. A compression spring 19 biases said pump element 18 against said secondary lever 11.

FIG. 2 shows the fuel injection pump of FIG. 1, wherein movement of said mixture control slide 16 and said support pin means 30, together with the lower end of said secondary lever 11 have resulted in an increased clearance 20 occurring at said power fulcrum 22, and an attendant reduction in stroke and flow.

FIG. 3 shows an alternate embodiment of the invention in a fuel injection pump 51 having a single lever 68. Sensor mechanism 80 is not shown, but as in FIG. 1 engages a threaded sensor control rod 57, which in turn engages a power fulcrum 74. The sensor mechanism operates the same as that of the preferred embodiment.

Pump details are again omitted except for a pump element 73, reciprocation of which causes pumping to occur, which slidably engages a bore in a transmission housing 52.

As before, an eccentric shaft 54, with an integral eccentric 53, is supported at said transmission housing 52 by a pair of bearings 55, which are pressed into bores 'of said transmission housing 52.

Said pump element 73 has an enlarged pump element head 71. A compression spring 72 bears against said transmission housing 52 and against said pump element head 71. Said enlarged pump element head 71 engages a recess 69 formed in boss 70 at the upper end of said lever 68. The opposite end of said lever 68 is biased against said eccentric 53 by a compression spring 67. Said compression spring 67 is positioned by a recess 78 and bears against its bottom.

A cover 56 covers the open top of said transmission housing 52, except for an aperature 58 through which said sensor control rod 57 extends.

A fulcrum slide member 59 is supported vertically by a self-locking idle adjustment screw 61, which engages a tapped hole 75 in said fulcrum slide member 59. Said idle adjustment screw is trapped between the lower surface of said cover plate 56 and a surface 76 of said transmission housing 52.

Said fulcrum slide member 59 has a guide slot 77 formed in it to guide said power fulcrum 74, and two supplementary fulcra 63, one of which is shown. Said supplementary fulcra 63 are disposed on opposite sides of said guide slot 77. Said power fulcrum 74 periodically bears against the bottom of said guide slot 77.

During a portion of each cycle, said supplementary fulcra 63 bear the load of said lever 68, allowing said power fulcrum 74 to be freely repositioned by said sensor control rod 57. I

A semi-permanent support screw 60 engages threads 79 in said transmission housing 52, and bears against said fulcrum slide member 59 at its upper end. .At its lower end, said fulcrum slide member 59 bears against a mixture-control cam 65 formed on a mixture control shaft 64. Said mixture-control shaft 64 is rotatably supported in two places by bores in said transmission housing 52. A mixture control arm 66 engages said mixture control shaft 64 outside said transmission housing 52.

In FIG. 4, the fuel injection pump of FIG. 3 is again shown except that said mixture control shaft 64 has been rotated clockwise by said mixture control arm 66. As a result, the lower end of said fulcrum slide member 59 has moved to the right, creating an additional clearance 49 between said power fulcrum 74 and the bottom of said guide slot 77. As said eccentric 53 turns, the stroke of the pump is reduced because of said additional clearance 49.

FIG. 5 shows a fuel injection pump 81 similar to that of FIGS. 1 and 2. Said support pin means 30 and said mixture control cam 65, and said mixture control arm 66 of the former figures are replaced by a conical screw means 93, comprising a threaded portion 95, which engages a tapped hole in a transmission housing 92, a stop flange 96, and a conical end 94 which engages a raised portion of said fulcrum slide member 59.

MODE OF OPERATION OF THE PREFERRED EMBODIMENT As eccentric 3 turns, primary lever 9 oscillates about its spherical seat 28 on primary lever support screw 10. This causes power fulcrum 22 to oscillate, which in turn causes secondary lever 11 to oscillate about its support at the shoulder 26 of support pin 12. Oscillation of secondary lever 11 causes pump element 18 to reciprocate and pumping to occur.

In open-throttle operation, with high intake manifold pressure, sensor mechanism lowers control rod 7 and power fulcrum 22 to a position approximately as shown in FIGS. 1 and 2. When the throttle is closed, as in idling, with low intake manifold pressure, sensor mechanism 80raises the control rod 7 and power fulcrum 22 approximately to the level of the supplementary fulcra 23. Thus the power fulcrum 22 is positioned according to fuel requirements of the engine.

When mixture control slide 16 is raised, as in FIG. 1, and eccentric 3 is at its nadir (as shown in all figures) in relation to primary lever 9, slight clearance exists between power fulcrum 22 and the two levers 9 and 11. This allows power fulcrum 22 to be freely raised or lowered by sensor control rod 7 during a portion of each cycle.

When mixture control slide 16 is lowered, as in FIG. 2, support pin 12 moves to the left, as does the lower end of secondary lever 11, creating additional clearance 20 as shown in FIG. 2. Now part of the excursion of power fulcrum 22 is used before it contacts secondary lever 11, thus reducing the amplitude of the oscillations of secondary lever 11, lessening the stroke of pump element 18, and reducing the rate of pumping.

Any of the adjustable pivotal support means shown for changing the position of a support (the screw, the cone and screw, the pin and slide, and the cam) can be arranged to work equally well with either type of fuel injection pump. The crux of the invention is that the fuel injection pumps will operate well with increased clearance, and that a device which increases the clearance can be an effective and inexpensive mixture control device.

Accordingly, the claims I make include:

I. A fuel injection pump comprising: an engine driven eccentric; a primary lever having two ends and engaging said eccentric at one end, and being pivotally supported at its other end by a semi-permanent support; a reciprocable pump element; a secondary lever having two ends and engaging said pump element at one of said ends; a power fulcrum positioned according to fuel requirements of the engine, said power fulcrum adaptable for periodically engaging said primary and secondary levers; a pair of supplementary fulcra engaging said secondary lever during a portion of each cycle; wherein the improvement comprises an adjustable pivotal support means engaging said other end of said secondary lever, whereby the clearance between said power fulcrum and said primary and secondary levers can be adjusted.

2. Apparatus according to claim 1 wherein said adjustable pivotal support means comprises a movable, sloping mixture control slide, and a slidable support pin means, said support pin means adaptable at one of its ends for pivotally supporting said secondary lever, and adaptable at its other end for engaging said mixture control slide.

3. Apparatus according to claim 1 wherein said adjustable pivotal support means comprises a mixture control cam adaptable for pivotally supporting said other end of said secondary lever.

4. Apparatus according to claim 1 wherein said adjustable pivotal support means comprises a mixture control screw means adaptable for pivotally supporting said other end of said secondary lever.

5. Apparatus according to claim 1 wherein said adjustable pivotal support means comprises a conical screw means adaptable for pivotally supporting said other end of said secondary lever.

6. A fuel injection pump comprising: a pump element; a lever having two ends, one of said ends engaging said pump element; an engine-driven eccentric engaging said other end of said lever; a fulcrum slide member having two ends, a fulcrum guide slot, and a pair of supplementary fulcra engaging said lever intermediate said pump element and said eccentric; a power fulcrum positioned according to fuel requirements of the engine, said power fulcrum adaptable for periodically engaging said lever and said fulcrum slide memher; a semi-permanent pivotal support engaging one end of said fulcrum slide member; wherein the improvement comprises an adjustable pivotal support means adaptable for engaging the other end of said fulcrum slide member whereby the clearance at said power fulcrum can be adjusted.

7. Apparatus according to claim 6 wherein said adjustable pivotal support means comprises a mixture control cam adaptable for supporting said other end of said lever.

8. Apparatus according to claim 6 wherein said adjustable pivotal support means comprises a mixture control screw means adaptable for pivotally supporting said other end of said lever.

9. Apparatus according to claim 6 wherein said adjustable pivotal support means comprises a movable, sloping mixture control slide, and a slidable support pin means, said slidable support pin means adaptable at one of its ends for pivotally supporting said fulcrum slide member, and adaptable at its other end for engaging said mixture control slide.

10. Apparatus according to claim 6 wherein said adjustable pivotal support means comprises a conical mixture control screw adaptable for pivotally supporting said other end of said fulcrum slide member. 

1. A fuel injection pump comprising: an engine-driven eccentric; a primary lever having two ends and engaging said eccentric at one end, and being pivotally supported at its other end by a semi-permanent support; a reciprocable pump element; a secondary lever having two ends and engaging said pump element at one of said ends; a power fulcrum positioned according to fuel requirements of the engine, said power fulcrum adaptable for periodically engaging said primary and secondary levers; a pair of supplementary fulcra engaging said secondary lever during a portion of each cycle; wherein the improvement comprises an adjustable pivotal support means engaging said other end of said secondary lever, whereby the clearance between said power fulcrum and said primary and secondary levers can be adjusted.
 2. Apparatus according to claim 1 wherein said adjustable pivotal support means comprises a movable, sloping mixture control slide, and a slidable support pin means, said support pin means adaptable at one of its ends for pivotally supporting said secondary lever, and adaptable at its other end for engaging said mixture control slide.
 3. Apparatus according to claim 1 wherein said adjustable pivotal support means comprises a mixture control cam adaptable for pivotally supporting said other end of said secondary lever.
 4. Apparatus according to claim 1 wherein said adjustable pivotal support means comprises a mixture control screw means adaptable for pivotally supporting said other end of said secondary lever.
 5. Apparatus according to claim 1 wherein said adjustable pivotal support means comprises a conical screw means adaptable for pivotally supporting said other end of said secondary lever.
 6. A fuel injection pump comprising: a pump element; a lever having two ends, one of said ends engaging said pump element; an engine-driven eccentric engaging said other end of said lever; a fulcrum slide member having two ends, a fulcrum guide slot, and a pair of supplementary fulcra engaging said lever intermediate said pump element and said eccentric; a power fulcrum positioNed according to fuel requirements of the engine, said power fulcrum adaptable for periodically engaging said lever and said fulcrum slide member; a semi-permanent pivotal support engaging one end of said fulcrum slide member; wherein the improvement comprises an adjustable pivotal support means adaptable for engaging the other end of said fulcrum slide member whereby the clearance at said power fulcrum can be adjusted.
 7. Apparatus according to claim 6 wherein said adjustable pivotal support means comprises a mixture control cam adaptable for supporting said other end of said lever.
 8. Apparatus according to claim 6 wherein said adjustable pivotal support means comprises a mixture control screw means adaptable for pivotally supporting said other end of said lever.
 9. Apparatus according to claim 6 wherein said adjustable pivotal support means comprises a movable, sloping mixture control slide, and a slidable support pin means, said slidable support pin means adaptable at one of its ends for pivotally supporting said fulcrum slide member, and adaptable at its other end for engaging said mixture control slide.
 10. Apparatus according to claim 6 wherein said adjustable pivotal support means comprises a conical mixture control screw adaptable for pivotally supporting said other end of said fulcrum slide member. 